FAETON-I is the highest direct-charged voltage plasma focus (PF), at 100 kV, 1 MA peak current. F-I produces consistent \(2.5 \times 10^{10}\) D-D neutrons/shot, over 3 MeV X-rays and \(\sim 350\) keV deuterons, demonstrating unique combined neutron-gamma environment. Its peak neutron yield was recorded at \(8 \times 10^{10}\) neutrons/shot at 12 Torr deuterium. The best peak dynamics-induced pinch voltage was measured at 194 kV. A major difficulty anticipated for PF operation at high-voltage and high-current is the likelihood of re-strikes which divert current away from the compressing plasma. F-I shows excellent current sheath dynamics and above-scaling D-D neutron yield, despite severe re-strikes. This study, correlating current and voltage time profiles with radial trajectories, reveals that the dynamics-induced voltage peak of \(\sim 150\) kV, produces deuteron beam first, then the re-strikes, which do not affect the target pinch plasma in geometry and areal density. Thus, this first neutron pulse is hardly affected by re-strikes, and the very high-voltage results in above-scaling out-performance, despite degradation of the second neutron pulse from pinch instabilities. Moreover, upgrading to D-T operation, it is expected that the first pulse at \(100-200\) keV (peak D-T cross section) ion energy, will completely dominate the second pulse with micro-beams at MeV (low D-T cross section).
